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Open a browser fallback for a media upload

POST
/v1/asset-upload-sessions/{upload_id}/browser
const handoff = await bird.assets.uploads.handoff(
  "aus_01krdgeqcxet5s7t44vh8rt9mg",
);
if (handoff.browser_url) console.log(handoff.browser_url);
Response200
{
  "session": {
    "id": "aus_01krdgeqcxet5s7t44vh8rt9mg",
    "state": "pending",
    "expires_at": "2026-11-04T23:00:00Z",
    "name": "Invoice",
    "alt_text": null,
    "folder_id": null,
    "file": {
      "filename": "invoice.pdf",
      "content_type": "application/pdf",
      "size_bytes": 1024,
      "sha256": "4e2090a479f7ce6b17ad31f991988f12571bcafbd4a441cc4063644fc1400ae0"
    },
    "result": null,
    "last_error": null,
    "next": [],
    "asset": null
  },
  "browser_url": "https://bird.com/dashboard/w/ws_01krdgeqcxet5s7t44vh8rt9mg/media-library/uploads/aus_01krdgeqcxet5s7t44vh8rt9mg",
  "next": [
    {
      "kind": "external",
      "description": "Open browser_url and have a person with asset write access select the original file and publish it. Their browser must reach the storage hostname. Opening the page does not complete the upload."
    },
    {
      "kind": "operation",
      "operation": "getAssetUploadSession",
      "params": {
        "upload_id": "aus_01krdgeqcxet5s7t44vh8rt9mg"
      },
      "description": "After the person finishes, read the saved result using the original workspace and connection."
    }
  ]
}

Offers an existing upload session to a signed-in person with asset write access in its workspace. Only the same OAuth connection or API key that created the session can request this fallback. The file, metadata, capacity reservation and one-hour deadline stay unchanged. Repeating the request returns the same page for a pending session. A non-pending session returns its current state without a browser URL. Enabling the handoff allows any currently authorized person in that workspace to complete or cancel it, independently of the original connection's continued access. The person must select matching file bytes; opening the page never publishes them.

Parameters

upload_idstring

ID of the media-library upload session.

Response Payload

session
object
required

The original upload session and any saved publication receipt. In this response, session.next is empty; follow the top-level next steps.

Show child attributes
session.id
string
required
session.state
string
required

Upload progress. Pending accepts a transfer; finalizing is checking and publishing it. Completed has a saved result. Rejected, cancelled and expired allow no new upload instruction or publication. An already issued upload URL can remain usable until its expiry.

Possible values: pending, finalizing, completed, rejected, cancelled, expired

session.expires_at
string
required

Absolute session expiry. Completion must finish before this deadline; starting it or refreshing an upload instruction does not extend it.

session.name
string
required

Frozen display name for a newly published asset.

session.alt_text
nullable string
required

Frozen alternative text, or null when omitted.

session.folder_id
nullable string
required

Frozen destination folder, or null for the library root.

session.file
object
required

Exact properties of the original file. Calculate size and SHA-256 from its bytes before creating a session. Images allow up to 5,242,880 bytes; other supported media allow up to 25,000,000 bytes.

Show child attributes
session.result
nullable object
required

Saved publication receipt, or null until completed.

Show child attributes
session.last_error
nullable object
required

Last completion error, or null when no failure is recorded.

Show child attributes
session.next
array of object
required

Available next steps for this session.

Show child attributes
session.next.kind
string
required

What you do about this step.

  • operation: call the operation named in operation, then read again.
  • external: act somewhere this API does not reach, then read again.
  • wait: nothing is asked of you, so read again later.
  • terminal: nothing you do resolves this, so stop retrying.

Tolerate a value you do not recognize: show the description and offer no action.

Possible values (may grow over time): operation, external, wait, terminal

session.next.description
string
required

A short, human-readable label for the step, suitable for display.

session.next.operation
string

The operationId to call. Present only when kind is operation. The operation's own schema says how to call it; this says only which one, and what to address it with.

session.next.params
object

The parameters that address the operation, by name: {"sender_id": "…"} for an operation on /v1/sms/senders/{sender_id}/requirements. A parameter the operation takes in its query string is given the same way, so an operation addressed as ?subject_id= carries {"subject_id": "…"}. Every parameter the call needs is here, whether its value came from the thing you were acting on or is fixed for this step, so you can make the call from this object alone. Present only when kind is operation and the operation names a subject. A request body, when the operation takes one, is described by the operation's own schema and never appears here.

session.next.url
string

A URL to open. Present only when kind is external, and only when the step has one. An external step whose description says to go and do something with no URL to open is normal.

session.asset
nullable object
required

Canonical asset when available, or null before completion or when unavailable.

Show child attributes
browser_url
nullable string
required

Bird page for a pending session, or null when it no longer accepts an upload. The link grants no access; the person must sign in and have asset write permission in the workspace.

next
array of object
required

Ordered steps to finish the fallback or read its outcome.

Show child attributes

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